Monitoring EBS

4 Types of EBS Storage, General Purpose (SSD) – gp2, Provisioned IOPS (SSD) – io1, Throughput Optimized (HDD) – st1, and Cold (HDD) – sc1
Throughput Optimized HDDs (ST1) and Cold HDDs (SC1), both CAN NOT BE USED AS BOOT VOLUMES!
Throughput Optimized HDDs (ST1) and Cold HDDs (SC1), both are not available in the drop list if the volume is the root volume. Adding an additional volume will allow these option types to become present in the drop list.
GP2 volumes have a base of 3 IOPS per GiB of volume size
Maximum volume size is 16 TB
Maximum IOPS size of 10K IOPS total (after which you need to move to provisioned IOPS storage tier)
Can burst performance on the volume up to 3K IOPS
Bursting uses I/O credits
Each volume receives an initial I/O credit balance of 5.4 million I/O credits
This is enough to sustain the max burst performance of 3K IOPS for 30 minutes (3K being the MAX iOPS available, including your standard 3 IOPS per GB. You can not burst an additional 3K to your standard, only burst up to a max of 3K)
If you need more than 3K IOPS then you need to increase the volume size accordingly via the 3 IOPS per GB rule
When not going over provisioned IO level (bursting) you earn credits back
Don’t need to know the calculation to replenish the credit balance
New volumes no longer require pre-warming, they receive their maximum performance the moment that they are available and do not require initialization / pre-warming.
When restoring a volume from snapshots, the first time you access the storage block, you can see a 5 to 50 % loss of IOPS due the volume either needing to be wiped clean or instantiated from a snapshot
Performance is restored after the data is accessed once
To avoid the performance hit, volumes can be pre-warmed
For a new volume, you should write to all blocks before using the volume
For a volume that has been restored from a snapshot, you should read all blocks that have data before using the volume
EBS CloudWatch Metrics:
VolumeReadBytes
VolumeWriteBytes
- Provides info on the I/O operations in a specified period of time
- The SUM statistic reports the total number of bytes transferred during the period
- The AVG statistic reports the average size of each I/O operation during the period
- The SampleCount statistic reports the total number of I/O operations during the period
- The Minimum and Maximum statistics are not relevant for this metric
- Data is only reported to CloudWatch when the volume is active
- If the volume is idle, no data is reported to CloudWatch
VolumeReadOps
VOlumeWriteOps
- The total number of I/O operations in a specified period of time
- To calculate the AVG IOPS for the period, divide the total operations in the period by the number of seconds in that period
VolumeTotalReadTime
VolumeTotalWriteTime
- The total number of seconds spent by all operations that completed in a specified period of time
- If multiple requests are submitted a the same time, the total could be greater than the length of the period
VolumeIdleTime
- The total number of seconds in a specified period of time when no read or write operations were submitted
VolumeQueueLength
- Then number of read and write operation requests waiting to be completed in a specified period of time
- If the count is high, it would be a good indicator to up the volume size to get more IOPS available via the 3 IOPS per GiB rule
VolumeThroughputPercentage
- Used with Provisioned IOPS (SSD) volumes only
- The percentage of IOPS delivered of the total IOPS provisioned for an EBS volume
- Provisioned IOPS SSD volumes deliver within 10% of the provisioned IPS performance 99.9% of the time over a given year
- During a write, if there are no other pending I/O requests in a minute, the metric value will be 100%
- A volume’s I/O performance may become degraded temporarily due to an action that was taken (such as creating a snapshot of a volume during peak usage, or running the volume on a non-EBS-optimized instance, or accessing data on the volume for the first time, if the volume wasn’t pre-warmed)
VolumeConsumedReadWriteOps
- Used with Provisioned IOPS (SSD) volumes only
- The total amount of read and write operations (normalized to 256K capacity units) consumed in a specified period of time
- I/O operations that are smaller than 256K each count as 1 consumed IOPS
- I/O operations that are larger than 256K are counted in 256K capacity units
VolumeQueueLength can come up frequently, know what it is
Volume Status Checks:
- OK:
  - I/O Enabled status:
    - Enabled (I/O Enabled or I/O Auto-Enabled)
  - I/O Performance Status:
    - Only available for Provisioned IOPS (IO1) volumes
    - Normal (Volume performance is as expected)
- Warning:
  - I/O Enabled status:
    - Enabled (I/O Enabled or I/O Auto-Enabled)
  - I/O Performance Status:
    - Only available for Provisioned IOPS (IO1) volumes
    - Degraded (Volume performance is below expectations)
- Impaired:
  - I/O Enabled status:
    - Enabled (I/O Enabled or I/O Auto-Enabled)
    - Disabled (volume is off-line and pending recovery, or is waiting for the user to enable I/O)
  - I/O Performance Status:
    - Only available for Provisioned IOPS (IO1) volumes
    - Stalled (Volume performance is severely impacted)
- Insufficient Data:
  - I/O Enabled status:
    - Enabled (I/O Enabled or I/O Auto-Enabled)
    - Insufficient Data
  - I/O Performance Status:
    - Only available for Provisioned IOPS (IO1) volumes
    - Insufficient Data
Degraded, Severely Degraded = Warning
Stalled or Not Available = Impaired
If your EBS volume is attached to a current-generation EC2 instance type, you can increase its size, change its volume type, or adjust its IOPS performance without detaching it
These changes can be applied to detached volumes as well
From the console (Volumes Console, Not EC2 Console), or from the API, Volumes can be modifed.
When modifying a volume, you can monitor the progress of the modification. If the size of the volume was modified, be sure to extend the volumes file system to take advantage of the increased capacity.

Monitoring EBS

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